A Troubling Adaptation: The Beautiful Teenage Brain

Fight club. Photo by Kitra Chana/National Geographic

Although you know your teenager takes some chances, it can be a shock to hear about them.

One fine May morning not long ago my oldest son, 17 at the time, phoned to tell me that he had just spent a couple hours at the state police barracks. Apparently he had been driving “a little fast.” What, I asked, was “a little fast”? Turns out this product of my genes and loving care, the boy-man I had swaddled, coddled, cooed at, and then pushed and pulled to the brink of manhood, had been flying down the highway at 113 miles an hour.

“That’s more than a little fast,” I said.

He agreed. In fact, he sounded somber and contrite. He did not object when I told him he’d have to pay the fines and probably for a lawyer. He did not argue when I pointed out that if anything happens at that speed—a dog in the road, a blown tire, a sneeze—he dies. He was in fact almost irritatingly reasonable. He even proffered that the cop did the right thing in stopping him, for, as he put it, “We can’t all go around doing 113.”

He did, however, object to one thing. He didn’t like it that one of the several citations he received was for reckless driving.

“Well,” I huffed, sensing an opportunity to finally yell at him, “what would you call it?”

“It’s just not accurate,” he said calmly. “ ’Reckless’ sounds like you’re not paying attention. But I was. I made a deliberate point of doing this on an empty stretch of dry interstate, in broad daylight, with good sight lines and no traffic. I mean, I wasn’t just gunning the thing. I was driving.

“I guess that’s what I want you to know. If it makes you feel any better, I was really focused.”

Actually, it did make me feel better. That bothered me, for I didn’t understand why. Now I do.

My National Geographic feature on the adaptive adolescent, The Beautiful Teen Brain, is now online. The take-home: This troublesome animal we call the teen, believe it or not, is adaptive.

Excitement, novelty, risk, the company of peers. These traits [defining adolescience] … make us more adaptive, both as individuals and as a species. That’s doubtless why these traits, broadly defined, seem to show themselves in virtually all human cultures, modern or tribal. They may concentrate and express themselves more starkly in modern Western cultures, in which teens spend so much time with each other. But anthropologists have found that virtually all the world’s cultures recognize adolescence as a distinct period in which adolescents prefer novelty, excitement, and peers. This near-universal recognition sinks the notion that adolescence is a cultural construct.

Culture clearly shapes adolescence. It influences its expression and possibly its length. It can magnify its manifestations. Yet culture does not create adolescence. The period’s uniqueness rises from genes and developmental processes that have been selected for over thousands of generations because they play an amplified role during this key transitional period: producing a creature optimally primed to leave a safe home and move into unfamiliar territory.

The move outward from home is the most difficult thing that humans do, as well as the most critical—not just for individuals but for a species that has shown an unmatched ability to master challenging new environments. In scientific terms, teenagers can be a pain in the ass. But they are quite possibly the most fully, crucially adaptive human beings around. Without them, humanity might not have so readily spread across the globe.

Get the rest here, for free. It includes some great photo work from Kitra Cahana. There’s also a rather luscious iPad version; you must download the free NatGeo iPad app, then use it to buy either the issue ($4.99) or subscribe to both print and iPad for a year ($19.99). Print subscribers should be getting their copies right about now. It’ll be on newsstands on Sept 27.

For those who like the science straight, here are some key papers I drew on:

Daniel Weinberger, Brita Elvaag, Jay Giedd, and Robert W M B Lum. 2005. “Brain : A Work in Progress.” Chief Executive (June). An expression of the “work in progress” interpretation of imaging results.

Jay Giedd, “The Teen Brain: Primed to Learn, Priimed to Take Risks,” Cerebrum, Feb 26 2009, at http://bit.ly/GieddPrimed. Another clear articulation of the adaptive view, from the researcher who did many of the scans and started off with a “work in progress” explanation. Nice adaptive flexibility on the researcher’s part.

Casey, B J, Sarah Getz, and Adriana Galvan. 2008. “The adolescent brain.” Developmental Review 28 (1) (March): 62–77. doi:10.1016/j.dr.2007.08.003. Another good overview from Casey, a leader in the field who will be on the live NPR Talk of the Nation program with me next week.

R. Douglas Fields. 2005. “Myelination: an overlooked mechanism of synaptic plasticity?.” The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry 11 (6): 528–531. Some of the myelination work, cited late in the piece, suggesting that the myelination state of the frontal cortex during adolescent allows for more fluid learning.

Wake, H, PR Lee, and R Douglas Fields. 2011. “Control of Local Protein Synthesis and Initial Events in Myelination by Action Potentials.” Science (New York. PDF download. Technical but awesome paper showing relationship between use and myelination of axons; supports Fields’ view, expressed in the article, that the period when an axon is myelinating is one of particular plasticity in brain development as well as behavior.

That should get you started. I’ll try to find time to post others soon. Chime in with more in the comments as you wish.